There has conventionally been proposed a method for thermal head energizing time control at astable voltage. For instance, there is a related method. Specifically, the conventional method is configured to control intermittent time of chopping pulse to be applied to a heat element so as to enable a thermal head to constantly secure stable heat even though power supply voltage varies due to load, etc. Thereby, print quality is constantly secured.
The conventional method has intended to set temperature rise of a heat element in the thermal head at a constant rate whereas an error of resistance value and ambient temperature of the thermal head have not been reflected for the control manner of intermittent time of chopping pulse.